Area Forecast Discussion
Issued by NWS Twin Cities, MN

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000
FXUS63 KMPX 231825 AAB
AFDMPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
125 PM CDT TUE SEP 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 322 AM CDT TUE SEP 23 2014

TODAY-TONIGHT...SFC ANALYSIS SHOWS AN AREA OF HIGH PRES CENTERED
OVER THE CENTRAL OHIO VALLEY REGION WITH ITS WRN EXTENT STILL
COVERING THE UPR MISS RIVER VALLEY THIS MRNG. ALOFT...AN UPR LVL
RIDGE IS CENTERED JUST ABOUT OVER MN...XTNDG SWD OVER IA/MO. WITH
THIS RIDGE SLOWLY MOVING EWD OVER MN INTO WI AND THE SFC HIGH PRES
ALLOWING FOR DECENT RADIATIONAL COOLING CONDS OVER ERN PORTIONS OF
THE WFO MPX CWFA WITH CLEAR SKIES AND NEARLY CALM WINDS...THE
COOLEST READINGS WILL BE FELT OVER WRN WI THIS MRNG. IN
ADDITION...PATCHY FOG IS ALSO BEING SEEN THIS MRNG WHEREAS THE MN
PORTION OF THE CWFA WITH WARMER TEMPS AND A MORE S-SE COMPONENT OF
WINDS ARND 5 MPH WILL REMAIN FREE FROM FOG DEVELOPMENT. ANY FOG
WILL GRADUALLY BURN OFF SHORTLY AFTER DAYBREAK...THEN ATTENTION
TURNS TO A COMPACT ROTATING UPR LEVEL LOW MAKING ITS WAY EWD OVER
THE NRN PLAINS. WITH A DEEP SLY FETCH AHEAD OF THIS UPR LOW
BRINGING IN HIGHER LEVELS OF MOISTURE TO BE WRAPPED INTO THIS
SYSTEM...ENHANCED OMEGA LIFT AHEAD OF THE LOW WILL BE RESPONSIBLE
FOR CREATING ISOLD TO SCTD SHWRS OVER WRN AND SRN PORTIONS OF THE
CWFA BY MIDDAY TDA. THOUGH CLOUDS WILL CERTAINLY BE ON THE INCRS
FROM THE SW...THE LACK OF A SFC LOW OR FRONT ALONG WITH DRIER
LOWER LEVELS WILL MAKE LOW LEVEL LIFT AND MOISTURE CONVERGENCE A
MITIGATING FACTOR TO BETTER PRECIP COVERAGE AND QPF AMOUNTS...BUT
WITH BETTER MODEL AGREEMENT ON AT LEAST -SHRA OVER SWRN PORTIONS
OF THE CWFA TDA AND EVEN THRU TNGT...HAVE MAINTAINED SLGT-LOW CHC
POPS FOR THOSE PORTIONS OF THE CWFA. SINCE THE UPR LVL LOW IS
XPCTD TO RUN INTO THE DRIER UPR RIDGE...OPEN UP TO A TROF AND LIFT
N...PRECIP IS NOT XPCTD TO MAKE MUCH MORE PROGRESS EWD THAN
CENTRAL MN THRU TNGT SO HAVE BEEN ABLE TO LEAVE MUCH OF ERN MN
INTO WRN WI DRY THRU THIS PART OF THE FCST PERIOD. EVEN THE TWIN
CITIES /AND THE I-35 CORRIDOR AS A WHOLE/ MAY HAVE A TOUGH TIME
RECEIVING PRECIP THRU THIS SHORT-TERM PERIOD BUT CANNOT BE RULED
OUT COMPLETELY SO SOME SLGT CHC POPS ARE INCLUDED ALONG AND W OF
INTERSTATE 35. AS FOR TEMPERATURES...AFTER QUITE THE SPREAD IN LOW
TEMPS THIS MRNG...RANGING FROM THE LWR 40S IN WRN WI TO THE LWR
50S IN WRN MN...TEMPS WILL EVEN OUT FOR HIGHS THIS AFTN INTO THE
LWR 70S UNDERNEATH AN EXPECTED DECENT COVERAGE OF CLOUDS...ALBEIT
MID-TO-HIGH LEVEL. MODEST WARM AIR ADVECTION TNGT WITH DEEP S-SW
FLOW AT THE SFC AND ALOFT ALONG WITH THE BLANKET OF CLOUD COVER
WILL SPELL MUCH WARMER TEMPS FOR OVERNIGHT TUE INTO WED. LOWS WED
MRNG WILL RANGE ARND 50 IN WRN WI TO NEAR 60 IN WRN MN.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 322 AM CDT TUE SEP 23 2014

MAIN FORECAST ISSUES OF NOTE WERE THE CONTINUED POPS THROUGH
WEDNESDAY NIGHT...WHICH RESULTED IN COOLER TEMPERATURES ON
WEDNESDAY. ALSO...INCREASED TEMPS LATER IN THE WEAK ABOVE GUIDANCE
BASED ON THE MASS FIELDS.

AT THE START OF THE PERIOD LIGHT RAIN SHOWERS SHOULD BE ONGOING
ACROSS THE WESTERN HALF OF THE FORECAST AREA. HIRES MODELS DEPICT
THIS...AND FORECAST SOUNDINGS OFF THE NAM/GFS SHOW DEEPER
MOISTURE...STRONGER VERTICAL MOTION...AND THEREFORE GENERATE MORE
PRECIP. MID LEVEL CLOUDS WILL LIMIT THE AFTERNOON HEATING...SO
DECREASED TEMPS ON WEDNESDAY...ESPECIALLY IN WESTERN WI.

AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE HIGH PLAINS AS THIS
SYSTEM GETS SHEARED APART IN THE NORTHERN STREAM. A THERMAL RIDGE
WILL BUILD TO THE WEST...AND BY FRIDAY AFTERNOON H850 TEMPS WILL
BE ON THE ORDER OF 17-19C ALONG THE MINNESOTA/DAKOTA BORDER.
FORECAST SOUNDINGS SHOW CLEAR SKIES...AND ALTHOUGH THE SURFACE
WINDS INITIALLY START OUT SOUTHEAST...AFTERNOON MIXING GRADUALLY
TRANSFERS SOUTHWESTERLY WINDS THROUGHOUT THE BOUNDARY LAYER WHICH
WILL BE A FAVORABLE SETUP FOR WARM TEMPERATURES...ESPECIALLY ALONG
THE MINNESOTA RIVER VALLEY. THIS SETUP HAS THE POTENTIAL TO BRING
MID AND EVEN UPPER 80S ACROSS WESTERN MN BY THE END OF THE
WEEK...SO RAISED TEMPS ABOVE THE MODEL CONSENSUS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 125 PM CDT TUE SEP 23 2014

HIGH CLOUDS SLOWLY STREAM IN FROM THE SW IN ADVANCE OF AN UPR LVL
LOW ROTATING OVER THE DAKOTAS. -SHRA WILL GRADUALLY SPREAD INTO
SWRN MN TODAY BEFORE DIMINISHING IN COVERAGE AS THEY HEAD TOWARD
THE REST OF SRN AND WRN MN TONIGHT. KRWF LOOKS TO HAVE THE BEST
SHOT AT SOME PRECIP LATE THIS AFTERNOON. NO SIGNIFICANT REDUCTIONS
IN CONDITIONS ARE XPCTD...ASIDE FROM AXN WHICH WILL LIKELY BECOME
MVFR THIS EVENING.

KMSP...VFR CONDS THROUGHOUT WITH GRADUALLY INCRG HIGH CLOUD
COVERAGE THAT WILL SLOWLY LOWER THRU TMRW MRNG. PRECIP CHCS ARE
QUITE LOW SO HAVE OPTED TO RUN WITH A DRY TAF...BUT IF ANYTHING...
ISOLD SHWRS MAY BE POSSIBLE AFTER 10Z-12Z TMRW. AND IF SO...NO
FLIGHT CONDITION REDUCTION IS XPCTD.

/OUTLOOK FOR KMSP/
WED...VFR. MVFR CIGS PSBL OVERNIGHT. WINDS SSE 12-15G25 KTS.
THU...VFR. WINDS S 7-10 KTS.
FRI...VFR. WINDS SSE 5-10 KTS.

&&

.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&

$$

SHORT TERM...JPC
LONG TERM...JRB
AVIATION...BORGHOFF





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